The present invention relates to a plasma processing apparatus, plasma processing method, and plasma processing analysis method for processing a semiconductor wafer using a plasma.
In order to obtain a fine pattern for a semiconductor device, etc. formed on a wafer, etching may be performed using a substance in an ionized state (plasma state) to remove a substance on the wafer by action of the ionized substance (reaction on the wafer surface).
The width and depth of the semiconductor device fine pattern and the processing speed of an etching apparatus for the fine pattern (etch rate) will be hereinafter called “etching result”. Due to various disturbances or change in the plasma state over time, it is difficult for the etching apparatus to achieve the same etching result even when processing is performed under the same etching conditions (hereinafter called “recipe”). For this reason, in order to stabilize the etching result, the etching apparatus adopts a control technique to change the recipe using apparatus monitor data obtained by measurement during etching (APC: Advanced Process Control). The monitor data is spectroscopic measurement data which is obtained by measuring the light emitted from the plasma during etching and the reflected light on the wafer surface by a spectroscope. The methods described in Japanese Unexamined Patent Application Publication No. 2013-105923 and Japanese Unexamined Patent Application Publication No. 2013-161913 are known as methods for adjusting the recipe using spectroscopic measurement data.
Japanese Unexamined Patent Application Publication No. 2013-105923 describes a method which uses, among apparatus monitor data including spectroscopic measurement data, a data parameter highly correlated with the etching result and adjusts the recipe based on the difference between the monitor data value and the target value for that data parameter.
Japanese Unexamined Patent Application Publication No. 2013-161913 describes a method which uses spectroscopic measurement data for data parameters highly correlated with the etching result (wavelength and time interval) among spectroscopic measurement data to estimate the etching result and adjusts the recipe using the estimation result.